At present, there are two methods for fabricating a filter disk for a color wheel. The first method includes a step of bonding a set of fan-shaped substrates which is coated with color filtering thin films to form a filter disk. The second method includes a step of patching a set of fan-shaped colors onto a round substrate, so as to fabricate a filter disk of color wheel.
For instance, in U.S. Pat. No. 5,868,482, a color wheel includes a plurality of fan-shaped substrates which are coated with color filtering thin films respectively, and are connected to a metal ring which is connected to a motor.
In U.S. Pat. No. 5,371,543, the color wheel includes a set of fan-shaped filtering thin films which are coated on a preformed round substrate to obtain a filter disk. The filter disk is driven by a motor to rotate at high speed.
The cutting process according to the prior art for preparation of the fan-shaped substrate and thin filtering films always suffers from unavoidable deviation and deficiencies that reduce the quality of the color filter. Furthermore, the deviation and deficiencies affect the appearance of the filter disk of the color wheel while the fan-shaped elements are glued together to form a filter disk, and thus also causing loss of dynamic balance, and induce a wind cutting noise when rotating at high speed and lower the service life of the color wheel.